There's two talks that are that you're going to see today we're going to see
a talk by first by Meghan gams who is
a researcher in the oceanography department at here at the University of Washington
and she talks about how the Missoula floods during the coming out of the last ice
age the role that they played in affecting not only the ocean
salinity but also that that effect that those floods had on the.
Atmosphere and and the climate and so the longer term impacts and then I'm going to
take you out of
a talk as well and take you really far back in time and I want to talk about.
Snowball Earth which is this idea that during the neo protozoa which is the time
period about six hundred eight hundred million years ago that the Earth's oceans
work completely covered with ice everywhere and so this is
a very exotic kind of idea but there's some strong evidence for it we seek to
understand it not only the changes that are happening. Right now and that are going
to the future that are being forced by changes were making so we're putting in
carbon dioxide in the atmosphere and that's having an effect on our climate but
what's actually interesting as well is the internal dynamics of the climate system
so what is the earth capable of experiencing in its range of climates just on its
own with out these kind of external forcings and I think those are interesting
questions too so it to be able to understand and I think you have to be able to
understand what. You know what what the what the climate of the future will look
like you really have to understand what the range of the variability of the climate
is. Under its own under under the Earth's own internal processes that are just
going on so. These two talks are more about. These these
these have some forcings which are. You know not anthropogenic in nature but are
processes that. Caused by long term geologic. Processes
So for example the Missoula floods are caused well were caused by
the earth coming out of the Ice Age And so as the earth is coming out of its ice
age things are warming up and water liquid water is starting to melt and it builds
up in these big lakes and it turns out that there was
a big lake near modern day Missoula Montana that. Was damned at one
in by basically
a giant chunk of ice OK so it's an ice we call an ice dam and that ice dam is
inherently unstable it's warming and it's going to be melting and eventually that
dam fails and when that dam fails it releases
a tremendous amount of water into what is now eastern Washington
and. And that's and that water actually carves out
a significant portion of the lower Columbia River. And then in my talk I'm talking
about snowball earth so snowball earth is. Probably cause it's
unknown exactly what caused the snowball earth but I think that it probably is due
to changes in the configuration of the continents and also has to do with the fact
that our. Our sun at that time was
a little dimmer and so. Yeah how can we understand the mechanisms of the climate
so I think I think what Megan is doing is
a terrific climate experiment so what she's kind of doing is seeing well what
happens if you have you know what is essentially the amount of fresh water that is
about the size of one of the one of the great lakes like Lake Superior. If that
enters into the ocean instantaneously so the oceans very salty OK And actually you
can actually And so what that means is that when you add that fresh water to it
you're freshening up
a tremendous amount of water in the ocean instantaneously and the ocean depends on
its saltiness in order to to mix so when you freshen up this water it allows it
allows mixing to happen in
a kind of an unprecedented rate but it is fairly restricted but what she's able to
see is that even these the single event of the Missoula flood has can have lasting
impact for years on the Earth's climate system and so we've seen other systems like
this you know there's a options
a volcano which you know can actually dramatically impact. The Earth's
Earth's earth's weather on the on the timescale of years to even decades. And
that's just single events and so but I think you know
a lot of big question that people have when they when we talk about climate change
is people always ask well is that is this
a natural system or is this a is this actually an anthropology or
a human caused thing that we're doing and so what we do is climate researchers
we're trying to discover and determine what are the
natural. What are what are the natural scenarios that are out there so what could
we achieve with climate change or what could we achieve. Without without these
anthropogenic forcings and then what we do is we see as what we seeing any
different from that and I think that the answer is yes so we are seeing climate
change that is different from any kind of natural forcings that we can give Ok so
we kind of we can kind of understand what the forcings are from volcanic eruptions
we we understood. And what the forcings are variations in the sun's intensity so
the sun. The sun is slightly less and get slightly more intense slightly brighter
and slightly dimmer over about
a ten year timescale and we understand the phenomena so yeah but I think it's I
think it's really important to be able to understand what the earth's climate is
the climate system is capable of on its own before we start making predictions
about where that climate system is heading under this external influence of adding
carbon dioxide to the atmosphere you know before I get started I just wanted to get
all of my acknowledgments out of the way so I want to think the engaged program for
letting me do this as well as town hall and the National Science Foundation who
funds my research along with both of my advisers land THOMPSON And Susan how to who
have the grant through the National Science Foundation I mean the school of
oceanography at the University of Washington which is under the umbrella of the
College of the environment and I'm part of the program on climate change so today
I'm going to talk to you about water rocks in the tropics and try to answer the
question did the Missoula floods impact climate. But before I get started with that
I wanted to give you
a little bit of background on how I got here so. As an
undergrad I studied these microorganisms called for
a minute for us and they tell you looking at the oxygen isotopes of these
you can understand when we have had. Ice Ages in the past
and then I went on and decided that I wanted to study vulcanology because I thought
it was totally cool and kind of exotic so I spent months and months
in the field with
a giant sledgehammer which was incredibly heavy and was out there during hunting
season which was unpleasant but. I got to look at all these really cool old rocks I
got to analyze and I thought that was really interesting but I sort of you know
this is millions of years ago and that's really cool but what happened to climate
when you have these huge volcanic events so I guess so I applied to graduate school
and I'm lucky enough to sort of marry that to looking at catastrophes but not just
at the catastrophe but what are the climatic implications of these catastrophes
and so this is me studying Oceanography in a Gumby suit on
a ship in the middle of the Pacific Ocean and in the middle of the civic ocean we
picked up this rock which is
a Columbia River basalt and it reached the middle of the ocean or
the bottom of the ocean by the missile floods and tell you about today so that this
would be a nice opener. Here's
a map of what the Earth looks like today so you see North America in the center and
all of the white is areas where we have ice sheets or ice so you can see that
there's. Ice in Antarctica and ice over Greenland and around the North Pole
but twenty thousand years ago we were in an ice age so that meant that there was
a lot more ice on land so you can see that the ice extent over Antarctica was much
greater and you see way more ice. Over the northern hemisphere and if you noticed.
The Continent seemed to be bigger during the last ice age and that's because sea
level was lower about four hundred feet lower than it is today so all of our.
Coastlines were much further out there today and that's because all of the water
from the oceans was taken up into these huge ice sheets and these ice sheets were
over a mile high so we're talking
a lot of our youth. So here is
a map of the Pacific Northwest today you can see the outlines of the state and
Seattle as indicated by the yellow star and here is
that. The lowering of sea level and the
extent of our coastline. Expanding during the Ice Age
This is the courtier and ice sheet which is a was
a minor ice sheet on the other side of North America we had the war entire ice
sheet which is this huge ice sheet and because it's very popular in scientific
research climate scientists have found that. During the last glaciation So when
these ice sheets began to melt. Water streaming from the warranty to
a sheet causes dramatic climate change it caused ocean circulation to slow down and
it caused. Changes in climate so
a cooling. Of the atmosphere but not many people have actually
studied the courtier in
a sheet the smaller one on the west coast of North America but this is what I study
so right here is glacially Missoula and glacially is the subject of today's
talk and I wanted to sort of explain what glacially is and sort of
a very schematic way so imagine a depression like
a valley so this is looking from above in
a map field and you have water that sort of pools in this depression or valley
and then along comes a lobe of that corridor. A glacier essentially just
a big glacier and so that it acts as
a dam with this water reservoir building behind it
but then periodically this ice dam fails in some way.
And then all of that water that was built up behind it in this reservoir is able to
flow out very quickly and so here's
a view of the actual valley that the reservoir of glacial existed in
and. That water half the volume of glaciers of Lake Michigan.
Flowed out within an order of hours Think about that so this is
a giant wall of water filled with icebergs and sediment and it's just
rushing out towards the coastline so along the way this very turbulent
water is picking up rocks and it's scouring out the landscape so that's how we get
the scab lands of eastern Washington if you're familiar on your way to.
Unless you're
a husky you know want to go there that's going to do. So but this is. This
is one of those boulders that has been scoured out and you can see how huge that is
and this is being carried by this flood so this is something that is tremendously
catastrophic in fact there's evidence that the the water reached over
a thousand feet high which is about two space needles tall so this is
a huge huge event that's happening very very quickly and recent work from the U.S.
Geological Survey has shown that the floods emptied out through the Columbia River
and into the Pacific Ocean within within an order of weeks of that ice dam
collapsing so this is happening when you think about. The ocean this is
happening basically immediately this is
a fast very very fast event. So there's been
a lot of work looking at where these floods flowed and here's So the black line
sort of shows you where schematically we had these flood events flowing but there
hasn't been a whole lot of work looking at what happens when you all of
a sudden dump all of this fresh water into the Pacific Ocean and that's where our
research comes in and what we ask is what happens when these floods reached the
Pacific Ocean and how can these floods impact limit and to do this we use
a climate model
a computer climate model so this is the same kind of model it's the same model
that's used to understand what the future climate looks like with increasing C O
two into the atmosphere except we're using this model and setting it up so it
simulates what the Earth was like twenty thousand years ago so that going back to
that first photo I had shown the first photo. Of the Ice Age The model has.
Kilometers of ice covering all of the continents and the lower sea level simulate
that So this is what the freshening looks like in our model so Seattle's marked by
the the Black Star and the the blue shape is where we have
said. Where we said this is where the flood happened so the salinity is
decreased so it appears as if we've dumped this fresh water in to the ocean but
before I go on to talk to you about more ocean stuff I kind of wanted to orient you
because it's often complicated to look at the ocean so so far we've been looking at
maps views of everything so that what that where have labeled ocean surface we've
been looking at that that view but now we're going to start looking at what happens
at depth so looking at the side sort of where the fish live and looking at the
actual ocean so to do that we. Sort of takes slices through the ocean
like along this red line and in. In
a vertical section it would look like this so that red line would be there and now
we're looking at it from the side is
a board with that. So
the brown there indicates where we have the continent and so the dark blue is the
ocean and then the lighter blue is the atmosphere and so North is. Heading away
from me on the stage and the equator is closest to me are we still good you guys
respond
a lot more. You're more verbose than many introductory oceanography classes.
So thank you. Well that's possible yeah. So here
is the North Pacific and that's what I was showing you before so we're kind of near
looking at the side view we're close to the Pacific Northwest and then by the
equator that's the tropical Pacific so in side view this is where we've
imposed the freshwater flood and this is what it looks like in the model
so in the left corner you see the picture that I showed you before from the model
and this is looking at
a side view so we freshened the top one thousand meters of the ocean and this is
sort of an intermediate flood event we believe so what we see and so what we see in
the model and what I've drawn for you to make it
a little bit easier to follow is initially there's mixing
and then that mixing changes ocean temperature and we find that on the perimeter of
where we have freshened the North Pacific you get warming on one side and cooling
on the other side and that allows heat to transfer
from the ocean to the atmosphere and when you're transferring heat we
energize the atmosphere. And I'll stop there for
a second and go back and talk to you about the tropical Pacific so keep this in
your mind we'll come back to in
a minute but I want to give you some background on the tropical Pacific because
it's of an incredibly dynamic and fascinating place and you need this background
before we move on to the next part so this is the tropical Pacific Ocean
this is the central the central America South America. Just to orient you
here's the equator five degrees north and five degrees south so those are lines of
constant latitude and this red blob here this is the Western Pacific warm pool
and so this is this warm water mass that is remains at
about eighty four degrees Fahrenheit or about twenty nine degrees Celsius all the
time it's really it's bathwater essentially in terms of warmth
and so that is able to stay near popular New Guinea and Australia by these trade
winds that blow from the east to the west but periodic Lee what
happens is these winds weekend or they reverse direction and head from west to
east which allows this warm pool of water to move towards the
eastern portion of the tropical Pacific and we have
scientists like to quantify that to sort of make measurements about this so what we
do is we look at. The ocean surface temperature in this box
which we call the Nino three point four region and we take the average of all of
the temperatures that we measure in this area between five degrees north and five
degrees south and we come up with
a single value. So the pictures shown here this would be
a lie niña event are you familiar with El Nino and La niña Yeah so during the
event you know you probably wouldn't want to get. Season ski pass here right
so. I'm going to go there.
So and then this would be an El Nino event where you have that warm water in this
box and so here is a map or Here's
a graph that shows the value of the average sea surface temperature in that region
through time so you can sort of by I pick out some big events
some warm times like the in one thousand nine hundred eighty three on the new event
and the one thousand nine hundred seven one thousand nine hundred eight event I
remember that one particularly because I remember being stuck at school until
midnight because the entire neighborhood was flooded and we had to wait for the
fire department to come and take us all home. But this is sort of difficult to look
at because it's sort of difficult to see where the only new events are and where
the La niña events are so what we end up doing is we look at sort of the. The
unusual years the differences from the average And so the red the red regions on
this graph show you when we've had only you know years and the blue tell you when
we have had years so again here's the one thousand nine hundred seven or here's the
one thousand nine hundred eighty two eighty three and then the one thousand nine
hundred seven one thousand and eight new events OK let's go back to this picture
so the atmosphere has been excited by this transfer of heat from the. From our
freshened region and that allows winds to spin up so we call those anomalous winds
but they're just unusual they're different from the norm. And so those winds
are very similar to these weekend trade winds or these reverse direction winds
and what we see with this these anomalous winds is that we see warmer ocean
temperatures and we're actually seeing is El Nino events that are triggered
by Missoula flood events and this is our.
Our version of that graph from the model and this isn't just one simulation this is
a combination of seven different runs that we did with the model where we freshened
at different times in the different years in the model and we still see the same
response that you're getting warming in the tropical Pacific within months of.
Flooding the North Pacific with glacial Eichmanns all that water so
although Lake Odyssey can change climate dramatically for long periods of time we
show that glacial can also change the climate and going back to thinking about the
new online niña you can remember that snow pack is not so great during one of the
new years and you can see that when you have an El Nino event this is
a map where it shows you every place where. Climate is impacted by
a new event so you see. The warm weather in.
In the Pacific Northwest and wet weather. In Southern California
and warm and dry conditions in Australia and pop and Danny and that's often when
you get those horrible forest fires. So what I've shown you is
that the Missoula floods are number one really cool but number two that they did
they do have global impacts which is really interesting and that's.
That's all I have for you.
Thank
you. I'm wondering if you look to me
like. After the flood that it got warmer because of in the
northwest and would do something to the glacier it was there
a positive feedback or feedback or something you know that's something that we want
to think about and start looking into Unfortunately the model we use the ice sheets
are static so they stay the same no matter what's happening to. Like
precipitation or temperature. But the new generation of models will start to have
what we call dynamic ice sheets so that they can change in response to temperature
changes or precipitation changes I guess I guess the bigger question involved in
that is like with climate change is it itself correcting or does it do the other
thing is that. You know that's what we worry about right like it is going to do
something to cause
a positive feedback loop in that it's going to go right yeah yeah
I had a question on your last night there was
a big northern part of the mix there's no other.
Color and I'm wondering what do you know I don't
know. OK. I pulled this from the no website if you can see from the bottom but I.
Those are my advisors who are in the audience you can correct me if I'm wrong but I
thought during years we had wet weather also in the Gulf of Mexico region.
And it's called colder than usual so I'm not sure why it's not the same color as
other things that are getting light and cold.
Thank you very much to short ones OK why does freshening the water increase the
amount of heat put into the atmosphere is it was freezing water right now is it was
hold water right and in these models we're not actually so we haven't set the
temperature to being cold so it's just the ambient temperature of the ocean in the
way that we've set up it was
a model Titian of more water that increases the energy in the atmosphere it's the
addition of water. We're still looking into exactly why that's happening but it has
to do
a lot with the way that we're putting in the freshwater and just. What happens is
you're having. Constant constant
the pressures it has to do with ocean dynamics in terms
of the when you put in that I call it when you put in this fresh and region it's
not stable it's it has to it some point mixed with the surrounding water and that
means that density surfaces have to change and that so may stop circulation or
something and therefore keep a local more heat in
a local area it's more it's more anomalous heat then yeah yeah
OK And how long did this phenomenon persist was it more than one season or
how many seasons this the only new event seems to happen there was triggered that
was checkered it steams to stick around for up to six months. Or so and now I don't
but we're going so this is just the initial. Connection to the tropics through the
atmosphere and we're starting to look at the model on the longer and longer term
seeing how this freshwater actually moves in the ocean and how that
eventually how that how that affects climate as well.
How big was the volume of water that was released. That caused this event it
was twenty one hundred kilometers cubed I don't know what it is an
imperial you know it's half the volume of of Lake Michigan or about the volume of
Lake Ontario twenty one hundred cubic kilometers and how often did this occur
because there were multiple There were multiple floods so they believe that
initially. The floods who are more infrequent but much bigger so these huge
catastrophic events and then later floods were much smaller so they think that it
could have been hundreds of years between initial floods but then later floods may
have been more frequent on the order of like fifty or twenty five years so that one
more than what what causes the water in the tropical Pacific to always be at
a constant temperature would seem that there must be
a heat source I think you said you went into the you know you know it doesn't
wondering if it's something because it's a sort of
a ring of fire or what what causes that it's more it was so the the water in that
area is all really warm and so maybe that picture made it look like
a two way warmer than surrounding water it's mostly just that that water is always
being heated and it's just being pushed into place and it's sort of staying there
it's not being able to and so it's moved around mostly solar heat solar radiation
that's yeah as in the winds keep employees. What's the relationship of that warm
water trade winds what's causing the trade winds and why are why isn't that
affecting the trade winds or do they somehow draw the trade winds to themselves so
the trade winds are so that has to do with the way the fact that
the Earth is rotating so we just have bands of wind OK that go in certain
directions in that certainly to see those bands go as from east to west. OK Thank
you yeah thanks for questions. With
this interesting model. Are you making your efforts or somebody making efforts to
look at the geologic record to see if some of these predictions actually help with
. Oh in terms of so there's some problems with that so. No
So there's so glacial
a Gaga sea which is the one on the East Coast there ton of there's
a lot of geologic evidence of what happened it's in conjunction with that. The
chemistry of the Pacific Ocean makes it very difficult for foreign minister as like
what I showed you before and other what we call paleoclimate proxy records. Means
of understanding what past climate looked like using like biological things like
form and if they can't survive the record doesn't survive in the Pacific very well
but we've got some in carrier basin and in Santa Barbara basin and shallower areas
but we have something called. The has to do with the acidity of the ocean for
example good look at tree rings in this old rate I did I spoke with somebody at
Colorado State University and. We haven't followed up but he was interested in this
and someone else seems like
a friend yeah and looking at this too you can see that you know other areas are
affected like Southeast Asia and we have records of monsoons. In
southern China and in India and I spoke with somebody from the University of
Toronto and he he was interested in looking at that as well so that is we haven't
done it yet but there may be things just less traditional than what's been used for
a glacial Odyssey but thank you for the question.
Of the night. We know how those floods from the multiple floods were time
correlated. Together. You know I don't I don't know the answer to that I'm
not and I haven't looked at the other floods in much detail but they were all
during this there is
a lot going on if you have one warm year this could happen to it I believe it's
feasible that that would happen that multiple flood would have in the same time and
there even more mega floods there's evidence of mega floods throughout Alaska as
well so it could be much bigger than dismissal. And less.
So yeah OK Yeah thank you for that. Thank you.
I thank you all for coming so I just want to start with this pretty iconic image of
Earth from outer space and to me this this image kind of demonstrates
a lot it demonstrates
a planet that is full of life with this diversity of life over
a lot of different land forms on this image you can see through this and deserts
you can see oceans and land and you can see clouds and ice but it also
suggests something else to me it kind of suggests that Earth is a part of
a greater universe because this is taken from space and it kind of makes you wonder
what else is out there well we've actually been able recently to answer that
question
a little bit and to see some other planets that are outside of our solar system so
I wanted to just start off by looking at some of these strange planets that we've
seen so far this is an artist's rendition of
a planet called co-wrote seventy. Now this is
a planet that's so close to its sun that at over four thousand degrees Fahrenheit
when it rains on this planet it literally rains liquid rock
this is a this is
a funny planet this is called. P one and this is known as the puffy as to planet
that we've found and that's because compared to Jupiter which is the largest planet
in our own solar system it's over twice as wide yet it contains less than
half of the stuff so you can think of this planet as being like a kind of
a giant puffball floating around in space or really kind of like
a marshmallow that's floating around
a campfire for all eternity and this planet is an artist's rendition of Kepler
sixty two F.
This planet is the planet that we think is most likely to have
a life outside of our solar system it's just the right distance from its sun that
it can have vast amounts of liquid water if they're present now here's
a strange planet this is
a planet with land and with oceans but it's
oceans are actually covered in ice and that ice is hundreds of feet
thick as
a matter of fact. So thick that light can't travel through that ice and that I sits
atop the liquid oceans the ice also flows over the
surface like big rivers of ice flowing around the globe
so you might look at this planet and you might say wow this is
a weird planet and it might seem like it's six hundred million miles away but it's
actually six hundred million years away because this is earth
or this was Earth. This is the snowball earth
or Earth as it looked like six hundred million years ago during
a time period that geologists call the neo proto result like
this is a time before animals and plants this is
a time before trees and dinosaurs but it's not
a time before life and so that's what my talk is about today
is how photosynthetic organisms or photosynthetic algae to be specific
survive that the snowball earth the vents of the neo protozoa So
this is my image of what I think of photosynthetic algae looks like in my brain.
I don't use microscopes so I don't really know. But you might ask why do I care
about algae like they're just what are they well we still have algae around today
but it turns out algae. Have done
a lot of cooling great things in their career how do you want on to evolve into
plants and evolve into trees and this evolution actually
set up the CO evolutionary habitat that allowed for animals like alligators
or the pygmy slaughter or human beings to exist
so to put it another way if it hadn't survived during the
snowball earth then. Plants wouldn't be here and animals wouldn't be here and you
and I would not be here so we really need to understand how these organisms survive
the snowball earth this extremely unique and different
time in the Earth's past so I like to think of this algae as like
a super hero like surviving the extreme events when there was the earth was
a near apocalypse so now you might ask
a little bit about the snowball earth OK this is really weird OK so the earth was
at oceans but they're frozen but they're not completely frozen TELL ME MORE OK Well
first there was the sun but this was really far in the Earth's past this is six
hundred million years ago and to give you some perspective the earth is only about
four point five billion years old and so it's actually so old that the sun was
a little bit dimmer so not quite as bright so things were
a little bit colder to begin with but then the other part of the story comes in is
that there's photosynthetic algae and these these are algae they eat carbon
dioxide and they produce oxygen and I have chosen to represent carbon dioxide as
this very warm mummy bag and I've chosen to represent oxygen as just some thin
sheets that you might get that wouldn't keep you very warm at night and the reason
I'm using This is because carbon dioxide when it's in the atmosphere has the
ability to warm
a planet and oxygen doesn't so if you convert carbon dioxide into
oxygen you're going to cool the planet and it turns out before the snowball earth
these algae were really productive and had lots of offspring and actually were able
to trigger this kind of event so causing the Earth's oceans to be completely frozen
over. So OK so that's really weird how do we get out of this like crazy snowball
that like the Earth's surface is completely covered Well the answer we think is
volcanoes so one thing that's cool about volcanoes is they don't really care if the
earth's surface is covered in ice they don't they don't really care if they pop up
in the tropics or if they pop up in Lascaux they're just going to do their thing
and so one thing that they do is they are wrapped and when they erupt they emit.
And ASH but they also emit gas and one of the gases they emit is carbon dioxide and
so over millions of years during the snowball earth the vents the carbon dioxide is
allowed to build up into the atmosphere doesn't have any place to go and eventually
the carbon dioxide builds up and builds up that it warms the entire planet creating
going from a very very cold planet to an extremely hot planet in just
a few thousand years so that's
a weird planet so where did these things survive during this time and I'm going to
kind of. Pose to you why that's why that's actually difficult answer to get to
so algae need two things to survive during this time they need liquid water has to
be liquid and they need sunlight so liquid water plus sunlight gives you the algae
OK so if we want to understand how we got from a snowball earth to
a present day Earth which is full of life and full of creatures we have to
understand where the photosynthetic algae survived so OK where did they survive
well here's an image of snow and that might be some people's first guess but at the
during the snowball it was below freezing everywhere all the time and so the snow
never had
a chance to melt into liquid water. So they couldn't survive on snow this is
a picture of
a volcanic hotspot that's underneath the ocean OK very warm there these things
would exist during a snowball earth and there's
a lot and there's liquid water plenty of it but there's no sunlight down that deep
so they couldn't survive there either but lakes so lakes of water right yeah OK
and. Why wouldn't they survive there well because either you're in a place on
a snowball where it's snowing all the time or you're at
a place where it's evaporating all the time and if you're
a place where it's snowing all the time well then that Lakes just going to be
filled in the snow and you don't have a lake and if it's
a vaccinating all the time well over the really long time periods the tens of
millions of years these snowballs lasted even the deepest lakes in the world would
eventually just completely dry out so we're going to need
a new idea and so where do the algae survive I don't think that they survived in
Africa but I wanted to point out one thing here I wanted to point out the Red Sea
which is sits between Africa and the Middle East and what I want to point out to
you is that at its southern edge the Red Sea is connected to the ocean but it's
also
a very long and narrow channel that has land on either side of it and
so I'm going to kind of explain to you and I call this kind of feature in Lynn sea
and we expect to see not necessarily the Red Sea during
a snowball earth but we expect to see features like
a Red Sea because of the geologic processes that formed the Red Sea So why do
I think that an inland sea or a narrow channel is
a good place for these photosynthetic organisms to survive well I'm going to try to
convince you that over the next couple slides. So this is an image of what the
continents might have looked like during Snowball Earth so you can see
a couple different things here you can see that you've got land and you also have
ice over the oceans and so like our present day Earth the
the tropics are the equal or is much warmer than the Poles but for
a snowball earth the tropics might be minus thirty degrees Celsius and the Poles
are much much much much colder and so because it's warmer at the tropics
and colder at the poles that creates a hydrologic cycle
a certain hydrologic cycle so at the equatorial have what's called sublimation so
sublimation is the process by which ice solid ice that's covering the ocean is
converted directly into vapor into gas so if you've ever seen dry ice you've
seen sublimation So you've seen that little block of dry ice just it doesn't melt
it doesn't go liquid it just turns into gas that sublimation process and that's
what happened to the ice at the equator during
a snowball earth but that sublimated water will transport to the poles where it is
deposit as ice so what that means is is that because it's colder and there's
snow falling at the poles the ice is really thick there and because it's warmer and
it the ice is supplementing at the tropics or near the equator the ice is is
relatively thin there it's still too thick to allow the light to get through but
it's relatively thin so because you have that slope or that that that
transition from thick ice to thinner ice it actually causes the ice to defy form
and flow under its own weight and that creates rivers of ice that flow from the
poles to the waiter. And so I could kind of draw
on we don't really know where these things might have been but I could kind of draw
on places near the equator or near the tropics where inland seas or these narrow
channels might have existed so why do I think inland seas or narrow channels are
a good place for these things to for algae to survive well I'm going to show you
a series of images and kind of like Megan I'm going to kind of run you through
a on the top is going to be a side view and on the bottom is
a top down view of the same thing so on the top we can see ice that's floating on
water and below that we can see ground and so imagine you have an algae
living down there during
a snowball earth well what's going to happen is that light from the sun
is going to try to make its way through this ice but the ice will end up absorbing
the light and so not enough light will get down there for those photosynthetic
organs for the algae to survive so algae can't survive underneath the ice
during
a snow ball or so if we're near the equator then we're at an area where you have
net sublimation so the ice the solid ice that's on the surface is being converted
or going away into the atmosphere it's turning to gas but you also have these
rivers of ice that are causing the ice to flow so what happens when
a river of ice encounters this kind of narrow channel it goes into this narrow
channel Well it slows down and you can kind of think of this as you know driving on
I five and then all of a sudden there's like
a big wreck and then you're down to one lane of traffic all of
a sudden things get slow when you get compressed and so this this ice that's
flowing through here will slow down as
a result of that but at the same time as it's being as it's slowing down it's also
being sublimated away so it's just leaving it's leaving go to go to the atmosphere
. So if that channel that narrow channel is long enough then eventually there just
won't be any ice left so if you were on this slow freeway and there were only
places to get off the freeway but not to get on that eventually you're going to
reach
a point there for you where there are there's just no more cars anymore so it's
kind of like that and so in this place where the ice that's covered the ocean can't
reach that is
a location where these photosynthetic organisms could survive during the snowball
or the vents so here's an image of what the Red Sea looks like and again this isn't
a real the Red Sea didn't exist during the snowball at the vents but we think that
places like it may have existed because the geologic processes that formed the Red
Sea were also present during the snowball earth events and so if you do
a calculation which is my research to calculate how far ice coming from the
southern end into the Red Sea would actually travel into that into that sea given
the the climate that we know like how fast the ice is is flowing and how how fast
the ice is sublimating away how fast it's being removed then what we find is that
under certain conditions it allows for
a little pocket of of water to remain that us that the ice that's covering the
ocean doesn't get to and so that's
a place where these photosynthetic organisms could have survived and lived
throughout the entire snowball or the bends so again if we want to look at
Earth today and understand the and appreciate the the diversity of life around us
and appreciate our own existence we really have to think these algae for surviving
during this novel or the vent because life as we know it wouldn't exist today if it
weren't for these photosynthetic organisms. So I kind of want to end with
a picture of Earth from space the one I started off with because I think that if
you look at if you were if you were on another planet and you were looking at Earth
right now with all of its different life and just and all of its diversity you
would say hey there's
a planet that has life on it for sure but if you were to look at Earth six hundred
million years ago during the snowball earth you would probably say that it was
a dead planet but so consider that when we're looking out of the stars and we look
at some of these strange planets that there might actually be life surviving the
seeds of life surviving and getting by in these nooks and crannies in these little
tiny spots just waiting to flourish when the climate changes all right thank you
very much I'll take your questions. Thank you.
OK question. Could you explain why the ice would sublimate rather than turn into
liquid was it just too cold for the liquid it would just some of it would just turn
to get this yeah so so the idea is that the surface temperatures are never warm
enough to actually melt it but they're happening because there's just wind in
things that will cause the ice to go into the atmosphere so it's never it has you
have to get above freezing to have melting but you don't have to get above freezing
to have sublimation. Since life existed in the earth for several billion years
before snowball earth with the other Snowball Earth yeah so that's
a great question so during the protozoa at the time that I was talking about like
six hundred million years ago there we think there were at least two Snowball Earth
events with there's evidence for maybe two more other than that during that same
time period plus there's evidence for another snowball earth that happened. Way
back in Earth's past like
a couple billion years ago but that was before these kind of organisms existed at
all so yeah so it's happened
a few times it looks like. So
six hundred million years ago that was animal life right no no they think there
might have been sponges. And so they survived yeah they have they had Yeah
they would have and so yeah there's those those kind of those so the photosynthetic
Henri's are really the what went on to make this is before plants for animals they
were like there's some evidence for sponges but it's I think that as far as it goes
that algae are really the most complicated lifeforms that existed during this time
. This noble or earth was
shortly before the Cambrian explosion you know there's
a huge speciation and the evolution of lots of diverse life the first one as I
understand it is two point two billion years ago and from what I've read. Shortly
there after cells within. The vault What is it about the
limitations of life that causes huge speciation and quick evolution afterwards yeah
that's
a really good question that I am completely on A quick to answer given my background
. So my my background is actually in Clichy ology so studying how I split was so
you can see why it's noble or it might be
a novel problems me but when it comes to evolutionary biology I you know I have
a very fundamental
a very fundamental understanding of it but not super technical so I mean but as far
as I know these are questions that people are still trying to answer like why do we
have this great diversity after these near catastrophes and I think it's really
unresolved as far as I know so. OK last
question. Well that's good because that was my first last question all right.
You said it it ended in
a thousand years that didn't make any sense to me. When you have they have to build
up oh yeah
a long period of time yeah I must have misspoken I meant to say tens of millions of
years yeah so. I'm sorry you know. And perhaps I
misheard I'm
a little deaf. There are organisms that live in snow Arthur bunch of other
places for life to survive rather than in liquid water yeah so animals presently do
survive in snow but it's no that does eventually get above melting occasionally and
this during the snowball earth we don't think that that every or no photo
synthesizers that exist in snow there are but it's places where it occasionally
gets above melting and you can have liquid water so yeah that it's
a particular kind and photosynthetic it's
a particular kind of photosynthetic algae and so if I can get
a little more deeper in the problem idea of the snowball earth is not like
scientists are still debating whether or not it happened and biologists are
actually people who are saying snowball earth couldn't have happened because
there's no environment for which them to survive so the onus is on geologists like
myself to kind of try and find these environments where they could have survived
icy are are you imagining that these are blue green algae or so yeah so there's
different blue green algae is the specific kind Yeah thank you yeah all right thank
you very much.